Scottish death certificates, or to be correct, 1855 and later death register entries, are problematic in terms of the information that they contain ..............
Birth register entries involve information provided most often by a parent so that the information is most likely to be correct, although fathers are notorious for getting the date of the marriage wrong, and a date, even place, of marriage that varies from birth registration to registration for a set of parents can be symptomatic of an irregular marriage that never ended up in the statutory register of marriages - "Haw hen, jist when did we git merrit by that declaration thingy, but?" - i.e. no [marriage] "lines" to refer back to that allow a check of the date and place .............
For marriage register entries the information is supplied by the couple marrying so is most likely to be correct, but errors are known to have occurred quite often for a number of reasons, including the inability to check what was written in the marriage schedule due to illiteracy; and the transcription process from the marriage schedule to the marriage register entry.
It's also not uncommon to find that the information on whether or not the parents were deceased at the time of the marriage is incorrect, both false positives and false negatives, sometimes, I suspect, due to the question being misunderstood. Whatever, this info is demonstrably more robust than the similar info re the fathers on an English marriage register entry, since Scottish registrars were specifically tasked with obtaining this information.
And so to Scottish death register entries

........ on the one side so much more valuable than the English equivalent, - with the name[s] of the spouse[s] including the maiden name[s] in the case of a male death; the names of both parents including the maiden name of the mother and any other previous or subsequent surnames if she had previously been married or had remarried; and the name of the informant (quite often a married surname if the informant was a married daughter); and their relationship to the deceased, and address if resident at an address other than that at which the death took place.
The other side of the coin is that this depended on the information provided by the informant.
In general the closer the relationship, the more accurate the information.
That written, however, I've seen situations where the information supplied by a son in terms of his grandparent was completely wrong and/or didn't supply information on other marriages of the deceased.
On the other hand I've seen death register entries where the information supplied by the governor of a poorhouse was immaculate in terms of the parents, including other surnames of the mother, and multiple marriages of the deceased, - this obviously goes back to the information originally supplied to the poor law inspector ........
In general, however, the highest accuracy of information is most likely to have been supplied by a sibling, followed by the spouse, followed by children, followed by nieces/nephews/uncles/aunts, followed by in-law relations (maybe not always correct in terms of the position in this hierarchy!), followed by more distant relations, followed by close friends (the term "intimate" is often used, but the meaning is different from today's meaning

), then neighbour, and finally one of a number of public officials.
But please, please, understand that this listing should only ever be taken as an outline guide. As noted previously, at any point in that list there can be much worse or better information in terms of accuracy than could most often expected.
And then we come to age of the deceased, or the marrying couple, for that matter !!
In a number of my relevant lectures I will pick out someone in the audience, with the typical dialogue as follows.....
Me: "How old are you?"
Audience Member: "60" [or whatever]
Me: "OK, but how do you know that?"
AM: "From my birth certificate, of course!"
Me: "OK, so let's imagine you were born before statutory/civil records were kept, - how would you know then?"
AM: [Typically starts to see where I'm heading] "Well I guess that I'd rely on what I'd been told, or maybe a baptismal record....."
Me: "But if the person registering your death hasn't access to any such information, then what would they report as your age?".
AM: ........ in general then concedes that the age reported on a death register entry is open to question, most especially if, as is often the case, the age reported conflicts with robust information from other reliable sources.
And then there's another factor which can greatly influence the age that appears on a death register entry ...........
This is the age that the deceased has previously represented to others that they are .......
The fairer sex are not unknown to want to be known as younger than they are, - there are many census records that show that someone miraculously ages by less, even much less, than 10 years between the decennial censuses, - and such folk are not always female !:
On the other side of the coin, given the greater regard paid to those of a guid age, it's far from unknown for someone to have exaggerated their age in terms of inflating the figure ............... so that an informant not connected to the family got it way wrong on the high side !!
Lots of food for thought, I'd have hoped
Orraverybest
David